1. Field of the Invention
The present invention relates to the field of liquid crystal displaying, and in particular to a backlight module that prevents corner leaking.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and is thus widely used. Most of the LCDs that are currently available in the market are backlighting LCDs, which comprise a liquid crystal panel and a backlight module. The operation principle of the liquid crystal panel is that liquid crystal molecules are interposed between two parallel pieces of glass and a plurality of vertical and horizontal fine electrical wires is arranged between the two pieces of glass, whereby the liquid crystal molecules are controlled to change direction by application of electricity in order to refract out light emitting from the backlight module for generating images. Since the liquid crystal panel itself does not emit light, light must be provided by the backlight module in order to normally display images. Thus, the backlight module is one of the key components of an LCD. The backlight module can be classified in two types, namely side-edge backlight module and direct backlight module, according to the position where light gets incident. The direct backlight module comprises a light source, such as a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (LED), which is arranged at the back side of the liquid crystal panel to form a planar light source that directly provides lighting to the liquid crystal panel. The side-edge backlight module comprises a backlighting source of an LED light bar arranged at an edge of a backplane that is located rearward of one side of the liquid crystal panel. The LED light bar emits light that enters a light guide plate (LGP) through a light incident face of the light guide plate and is projected out through a light emergence face of the light guide plate, after being reflected and diffused, to thereby form a planar light source for the liquid crystal panel.
As shown in FIGS. 1-2, which is a schematic view showing the structure of a conventional LED backlight module, the backlight module comprises a backplane 100, an LED light bar 300 arranged at one side of the backplane 100, and a light guide plate 500 arranged on the backplane 100. To simplify assembling and lower down cost, the light guide plate 500 is positioned by four rubber blocks 700 arranged at four corners of the backplane 100. The light guide plate 500 is provided, at one side thereof distant from the light bar 300, with a side reflector plate 900 mounted thereto to reflect light into the light guide plate 500 in order to improve utilization rate of light. The side reflector plate 900 is arranged between the light guide plate 500 and the rubber blocks 700. When the light guide plate 500 expands or contracts due to be affected by temperature variation, which causing reciprocal abrasion between the side reflector plate 900 and the rubber blocks 700, separation between the side reflector plate 900 and the light guide plate 500 may easily results at ends thereof, eventually leading to corner leaking in the backlight module.